1. Field of the Invention
This invention relates to compositions for leather treating and processes for their use.
2. Description of the Prior Art
Chrome and/or mineral tanned leathers are at present retained with syntans, vegetable extracts and/or resins of various types. This is done to impart retan effects or characteristics which chrome and/or mineral tanned leather does not of itself possess. The effects or characteristics include: bleaching, dye assisting, plumping, increased weight, less shrinkage, better feel, better grain character, and buffability. Conventional retan material generally imparts to chrome and/or mineral tanned leather a positive characteristic of rewetting and water absorption. Conventional leather lubricants applied as emulsions (fatliquors) generally add to this characteristic of wetting. Various materials such as: hydrophobic rubbers and resins, fluorocarbons, fatty chrome complexes, silicones, and waxes, are applied on top of conventional retan and fatliquor treatments to overcome the undesirable rewetting and water absorption characteristic imparted by these treatments. In many cases the result is sub-standard. Known attempts to overcome this problem include the use of a fatliquor containing a polybasic acid ester (U.S. Pat. No. 2,950,950) and the use of a fatliquor containing an alkyl phosphate (U.S. Pat. No. 3,010,780). More recently, complete fatliquor systems incorporating alkyl phosphates as emulsifiers for leather oils have been developed to overcome the deficiencies of the above approaches. All of the above systems are effective in lubricating leather, but do not supply a sufficient degree of internal water resistance unless used in In order to achieve increased internal water resistance with the above systems, sufficient fatliquor must be added to penetrate the leather deeply, resulting in poor leather character and quality.